I had my surgery in October and can tell you that what you were experiencing I was as well. I did have strong painkillers that I had to take for two weeks after discharge from hospital together with blood thinning injections and surgical socks. I was on a liquid only diet for the first two weeks, progressing slowing to a pureed diet which is where I am now. I'm not able to tolerate more fibrous foods yet (such as chicken even when pureed). I'm now four weeks on and all has settled down.
As for the shoulder pain, i sometimes get it but find that strong paracetamol (2x500mg) stops it immediately.
I'm now in week five of recovery, and feeling much better for the surgery, but still a long way to go - I really get the feeling that there are very different recovery processes whether on your in the UK (like me) or the USA - am not sure why.
So from a UK perspective - I was told the following - expect to be on a liquid diet for at least the first two weeks (very true), move slowly onto a pureed diet (very true again) focussing on small portions and six meals a day (again very true), as and when you can tolerate a pureed diet move onto the next stage of soft foods (some things I can tolerate - others are just not working right now) and when comfortable slowly move to a more substantial offering.
From reading on here some of the great contributors talk about it taking six months for a full recovery and others faster and slower than that.
My main learning is that I have to listen to my body, and to my tummy, rest when necessary and get out to walk as well (which whilst tiring moves things through). I have had to be extremely patient (not very good at that) and take each day as it comes - I have my up days and my down days. However, I don't have any reflux anymore or any burning sensations, which is a massive up side.
I'm not sure what post operative checks you had but I had to endure a barium swallow 48 hours after my operation which showed that the operation had been a complete success - did you have the same done? If not, it might be worth asking your consultant?
I wish you well and hope this is of some comfort and help.